Centrifugal pump.



F. W. KROGH.

CENTRIFUGAL PUMP.

APPLICATION FILED AUG. 11. i908.

l ml wfin Patented June 1, 1915.

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CENTRIFUGAL PUMP.

APPLICATION FILED AUG. 11, 1908.

l 9 1% 1 5@& Patente June 1, 19150 2 SHEETS-SHEET 2.

FERDINAND W. KROGH, OF SAN FRANCISCO, CALIFORNIA.

CENTRIFUGAL PUMP.

Specification of Letters Patent.

Patented June 1, 1915.

Application filed August 17, 1908. Serial No. 448,974.

To all whom it may con ern:

Be it known that I, FERDINAND IV. Knoon, of San Francisco, State of California, have invented certain new and useful Improvements in Centrifugal Pumps, whereof the following is a specification.

My invention relates to the balancing of the impeller wheel whereby it is caused to float, as it were, in the liquid on which it is operating, and end thrust is avoided.

To this end I provide one or more suction chambers opposite the suction supply of the pump to counterbalance the weight ofthe indrawn liquidone of these chambers is normally open and constitutes a communieating passage with a normally closed chamber which latter is opened by a movement of the impeller under the suction of the indrawn liquid, and is thereby thrown into action to oppose said suction and return the impeller to its normal position. The normally open chamber is of smaller diameter than the suction supply, and the normally closed chamber is annular and surrounds the open chamber, and is of greater diameter than the suction supply. As entrained gritty matter in the water pumped, rapidly cuts the moving parts, I apply a packing ring, and sometimes wearing rings also, to control the leakage into said chambers from the discharge space of the pump.

In the accompanying drawings I have shown portions of two centrifugal pumps containing my invention.

Figure 1 is a sectional elevation of part of a pump with a horizontal shaft and a ve r tical impeller. Fig. 2 is a sectional elevation of part of a pump with vertical shaft and horizontal impeller.

In the figures; l is the casing.

2 is the suction opening.

3 is the suction pipe particularly shown in Fig. 1.

4 is the impeller.

5 is the impeller shaft.

6 are packing rings between the impeller and the casing.

7 are springs for pressing said packing rings against the casing.

8 are wearing rings between the impeller and the packing rings 6 and preferably attached to the impeller.

9 is the step-bearing of the vertical shaft pump.

10 is a cup containing lubricant for the step-bearing.

11 is a chamber formed in the casing impeller, or either of them opposite the tion supply 2.

12 are channels maintaining an open conr munication of chamber 11, with the interior of the impeller.

13 is a normally closed chamber between the impeller and the caring and formed by rccessing either or both of these parts.

14 is an annular flange on the impeller which closes against an adiacent bearing on the casing either by abutting against the latter. as seen in Fig. 1 or by sliding within the same as seen in Fig. 2. or otherwise.

15, are wearing rings on the impeller flange 14 where it contacts with the casing.

16, are similar wearing rings on the casing in position to contact with flange 14 or its wearing ring.

17, is the space within the casing at the side of the impeller on the suction side. 18, is the similar space opposite the suction side. These spaces 17 and 18 are in communication with the discharge of the pumpthere is therefore a pressure against the impeller in these spaces, and the radial dimensions of the spaces are gaged to balance the impeller as nearly as possible. Under the in fluence of the pressure more or less water will leak from space 18 into chamber 13 and create a pressure therein as long as that chamber remains closed. Hence in a horizontal-shaft pump as in Fig. 1 the space 17 is approximately equal to space 18 and chamber 13 combined. while in a vertical shaft pump, as Fig. 2 the space 17 is smaller so as to leave a surplus of pressure upward to help counterbalance the weight of the shaft and the impeller.

In operation, the impeller being rotated creates a suction through opening 2. This tends to suck the impeller to that side and causes great friction and wear when not counteracted. which causes the suction at 2 tends to create a vacuum in chamber 11. If now the impeller moves toward opening 2 the contacting points between flange 14; and the adjacent surface of the casing are separated and the suction in chamber 11 is transmitted to chamber 13. These parts are so proportioned that the full suction of 11 and 13 combined is greater than that of 2 while the suction of 11 alone is less than that of 2.

and

suc-

-The wheel then will oscillate between these two positions until it reaches a mean posi- The same force, however,

librium.

Obviously the above structure may be variously modified without departing from the spirit of my invention.

Having thus described my invention, I claim,

1. In a centrifugal pump the combination with the casing and the impeller therein, an intermittently closed pressure chamber in the impeller and an open face vacuum chamber in the casing, an annular outward projecting flange on said impeller'abutting the outer edge of said vacuum chamber and adapted to form 'suction conmiunication with said pressure chamber.

2. In a centrifugal pump the combination with the casing and the impeller therein, an annular pressure chamber in the impeller surrounding the hub thereof and a vacuum chamber in the casing surrounding the impeller shaft, an annular outward projecting flange on the impeller, forming the inner wall of the pressure chamber, adapted to establish communication between said chamber and the vacuum chamber, and a removable Wearing ring at the outward end of said projecting flange engaging corresponding wearing ring on said casing.

3. In a centrifugal pump, the combination with the casing and the impeller therein, a suction inlet at one side of the impeller, a depression in the casing opposite said suction inlet forming a vacuum chamber around the impeller shaft, a series of channels in said impeller, permanently communicating said vacuum chamber with said suction inlet, an intermittently closed annular pressure chamber in the impeller around said channels adapted to form a suction chamber by the lateral movement of the impeller and a flange in said impeller provided with a removable Wearing ring adapted to open and close communication between the vacuum and suction chambers.

In testimony whereof, I have hereunto signed my name in the presence of two witnesses this 7th of August 1908.

FERDINAND W. KROGH.

Witnesses:

A. S. P11121 1, ALFRED FUHRMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

